Explanation: turn the percentage into a decimal, like for number 4 make it 0.40
then divide it by 30
Really hopes this helps!
n + q = 35
n = 35-q
0.05n + 0.25q = 8.15
0.05(35-q) +0.25q = 8.15
1.75 -0.05q + 0.25q =8.15
1.75 + 0.20q = 8.15
0.20q = 6.40
q = 6.40 / 0.20 = 32
32 quarters and 3 nickels
